#!/usr/bin/env python3
# -*- coding=utf-8 -*-
# 题目：画图，学用line画直线。


def f1():
    from tkinter import Canvas
    from tkinter import mainloop
    from tkinter import YES
    from tkinter import BOTH

    canvas = Canvas(width=300, height=300, bg="green")
    canvas.pack(expand=YES, fill=BOTH)
    x0 = 263
    y0 = 263
    y1 = 275
    x1 = 275
    for i in range(19):
        canvas.create_line(x0, y0, x0, y1, width=1, fill="red")
        x0 = x0 - 5
        y0 = y0 - 5
        x1 = x1 + 5
        y1 = y1 + 5

    x0 = 263
    y1 = 275
    y0 = 263
    for i in range(21):
        canvas.create_line(x0, y0, x0, y1, fill="red")
        x0 += 5
        y0 += 5
        y1 += 5

    mainloop()


f = f1
if __name__ == "__main__":
    f()
